I have a large lump on my penis and it hurts when I masturbate what should I do??

Stop masturbating and see a doctor.
Simples.

It's routine for a doctor to remove it or drain it if it's a cyst, with minor surgery. You can say why and when it hurts and doctors hear it every day, so no need to be embarrassed. A parent should just take you to the doctor without getting upset about anything to do with masturbating or picking up diseases. You could show him or her how many times this gets asked here.